One of the twins has the middle name of Faith. The middle name of the other is Hope.

It is not hard to believe that some of both will be needed in about two weeks when Erin Faith Buckles and Jade Hope Buckles are to be surgically separated after spending their brief lives as conjoined twins.

The girls are the daughters of a Woodbridge couple in their thirties: Melissa Buckles, a high school English teacher who is on indefinite leave, and Kevin Buckles, a Marine gunnery sergeant who is in the Drum and Bugle Corps.

The little girls have overcome enormous odds already. When delivered Feb. 26, at National Naval Medical Center in Bethesda, they were described as one of only about 700 sets of conjoined twins born alive.

The girls are the first set of such twins born in the Washington area in more than 20 years.

Kevin Buckles, an assistant drum major, has a son, Kevin Jr., from a previous relationship. The Buckleses also have a daughter, Taylor, who is 2 years old.

The girls have managed to impress doctors with their personalities.

In April, the two were active enough that one struck the other in the face. At an exam, Jade placed her hand on Erin's eye, making one doctor wonder whether they should be restrained for safety.

"No," said surgeon Gary E. Hartman, "the other infant does defend herself."

After a preliminary procedure last month, plastic surgeon Michael Boyajian reassured the parents.

"They're tough little kids," he said.

Faith and hope are terms that come naturally to the parents.

There was a point, after one of the medical briefings, when Kevin Buckles expressed to the doctors his and his wife's view that the twins' survival would be up to God alone.

"When all is said and done," he said, "we realize that it's not in your hands."

Both parents have appeared able to withstand the stresses of the intricate medical briefings they have received.

In her first year of college, Melissa took premed courses, and Kevin told a reporter that his position was "give it to me as you see it. . . . Don't be afraid to tell me."

Melissa described her husband as "just really calm" under the stress of anticipating an earlier procedure. Of herself, she said, "I kind of do the what-ifs once in a while."

The girls, delivered by Caesarean section, are joined along the abdomen and chest; each has her own limbs.

The birth has confronted the parents with constant challenges to their ingenuity, such as lining up the snaps on footed pajamas to make two sets into one. Diapers have to be put on sideways, since the babies face each other. For weeks, every bottle and diaper has been logged.

Even burping has been unique. "Sometimes I pat one's back," Melissa said, "and the other one burps."

But the parents know that they face challenges. "We're not foolish enough to think it will be a walk in the park," Kevin said in April.

Cardiologist Michael Slack, doing a catheterization on Erin and Jade.